arc: cache - utilize IO coherency (AKA IOC) engine

With release of ARC HS38 v2.1 new IO coherency engine could be built-in
ARC core. This hardware module ensures coherency between DMA-ed data
from peripherals and L2 cache.

With L2 and IOC enabled there's no overhead for L2 cache manual
maintenance which results in significantly improved IO bandwidth.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h
index 667f218bd808d669c17a4d3cd02150a39d25094c..cf999b0280d672c79a08f4bc2a5f2c6254fd7ff2 100644 (file)
--- a/arch/arc/include/asm/arcregs.h
+++ b/arch/arc/include/asm/arcregs.h
@@ -53,6 +53,13 @@
 #define ARC_AUX_SLC_INVALIDATE 0x905
 #define ARC_AUX_SLC_IVDL       0x910
 #define ARC_AUX_SLC_FLDL       0x912
+#define ARC_BCR_CLUSTER                0xcf
+
+/* IO coherency related auxiliary registers */
+#define ARC_AUX_IO_COH_ENABLE  0x500
+#define ARC_AUX_IO_COH_PARTIAL 0x501
+#define ARC_AUX_IO_COH_AP0_BASE        0x508
+#define ARC_AUX_IO_COH_AP0_SIZE        0x509
 
 #ifndef __ASSEMBLY__
 /* Accessors for auxiliary registers */

diff --git a/arch/arc/lib/cache.c b/arch/arc/lib/cache.c
index 8089f9df1e2602fbde9cdaf7f5f931893f40ca4e..56988dda18dd3d230a91f77c12cbe25f1eb37f3f 100644 (file)
--- a/arch/arc/lib/cache.c
+++ b/arch/arc/lib/cache.c
@@ -39,6 +39,7 @@ int icache_exists __section(".data");
 #ifdef CONFIG_ISA_ARCV2
 int slc_line_sz __section(".data");
 int slc_exists __section(".data");
+int ioc_exists __section(".data");
 
 static unsigned int __before_slc_op(const int op)
 {
@@ -147,6 +148,21 @@ static void read_decode_cache_bcr_arcv2(void)
                slc_exists = 1;
                slc_line_sz = (slc_cfg.fields.lsz == 0) ? 128 : 64;
        }
+
+       union {
+               struct bcr_clust_cfg {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+                       unsigned int pad:7, c:1, num_entries:8, num_cores:8, ver:8;
+#else
+                       unsigned int ver:8, num_cores:8, num_entries:8, c:1, pad:7;
+#endif
+               } fields;
+               unsigned int word;
+       } cbcr;
+
+       cbcr.word = read_aux_reg(ARC_BCR_CLUSTER);
+       if (cbcr.fields.c)
+               ioc_exists = 1;
 }
 #endif
 
@@ -191,6 +207,17 @@ void cache_init(void)
 
 #ifdef CONFIG_ISA_ARCV2
        read_decode_cache_bcr_arcv2();
+
+       if (ioc_exists) {
+               /* IO coherency base - 0x8z */
+               write_aux_reg(ARC_AUX_IO_COH_AP0_BASE, 0x80000);
+               /* IO coherency aperture size - 512Mb: 0x8z-0xAz */
+               write_aux_reg(ARC_AUX_IO_COH_AP0_SIZE, 0x11);
+               /* Enable partial writes */
+               write_aux_reg(ARC_AUX_IO_COH_PARTIAL, 1);
+               /* Enable IO coherency */
+               write_aux_reg(ARC_AUX_IO_COH_ENABLE, 1);
+       }
 #endif
 }
 
@@ -359,18 +386,26 @@ static inline void __dc_line_op(unsigned long paddr, unsigned long sz,
 
 void invalidate_dcache_range(unsigned long start, unsigned long end)
 {
-       __dc_line_op(start, end - start, OP_INV);
 #ifdef CONFIG_ISA_ARCV2
-       if (slc_exists)
+       if (!ioc_exists)
+#endif
+               __dc_line_op(start, end - start, OP_INV);
+
+#ifdef CONFIG_ISA_ARCV2
+       if (slc_exists && !ioc_exists)
                __slc_line_op(start, end - start, OP_INV);
 #endif
 }
 
 void flush_dcache_range(unsigned long start, unsigned long end)
 {
-       __dc_line_op(start, end - start, OP_FLUSH);
 #ifdef CONFIG_ISA_ARCV2
-       if (slc_exists)
+       if (!ioc_exists)
+#endif
+               __dc_line_op(start, end - start, OP_FLUSH);
+
+#ifdef CONFIG_ISA_ARCV2
+       if (slc_exists && !ioc_exists)
                __slc_line_op(start, end - start, OP_FLUSH);
 #endif
 }
@@ -382,18 +417,26 @@ void flush_cache(unsigned long start, unsigned long size)
 
 void invalidate_dcache_all(void)
 {
-       __dc_entire_op(OP_INV);
 #ifdef CONFIG_ISA_ARCV2
-       if (slc_exists)
+       if (!ioc_exists)
+#endif
+               __dc_entire_op(OP_INV);
+
+#ifdef CONFIG_ISA_ARCV2
+       if (slc_exists && !ioc_exists)
                __slc_entire_op(OP_INV);
 #endif
 }
 
 void flush_dcache_all(void)
 {
-       __dc_entire_op(OP_FLUSH);
 #ifdef CONFIG_ISA_ARCV2
-       if (slc_exists)
+       if (!ioc_exists)
+#endif
+               __dc_entire_op(OP_FLUSH);
+
+#ifdef CONFIG_ISA_ARCV2
+       if (slc_exists && !ioc_exists)
                __slc_entire_op(OP_FLUSH);
 #endif
 }